My 1993 Lexus Es 300 went on a trip to Baton Rouge, La and when I got there I noticed my power steering was low so I went and bought some power steering fluid from advanced auto parts with stop leak. I t work for a few minutes and was low again so that tell there is a leak somewhere and another is that Last Thursday I left my radiator cap off and drove the car and the car ran hot!! I bought another cap filled the radiator fluid back up and ran the car.. It ran hot for a few minutes and then went back to proper lowel. On the road to Baton Rouge this weekend I notice that when I stopped to temperature goes up, not to hot or anything but it does climb and then when I drive it goes back down? Any suggestions?